This invention relates generally to polyfluorinated, branched-chain diols and diisocyanates, methods of synthesizing them and polyurethanes prepared therefrom.
Fluorine is known to impart useful properties to polymers, including thermal stability, low-temperature flexibility, solvent resistance, marine antifouling properties, etc. Also, polyurethanes are known to be one of the most versatile of the polymer systems. Mixtures of diols and diisocyanates can be cured to polyurethanes at low temperatures, and the degree of cross linking can be controlled by adding varying amounts of triols.
A method of synthesizing perfluoroalkylene bis(ethylamines) having the formula NH.sub.2 --CH.sub.2 CH.sub.2 --(CF.sub.2).sub.n --CH.sub.2 CH.sub.2 --NH.sub.2, wherein n is a whole number of from 4 to 16, inclusive, is disclosed in U.S. patent application Ser. No. 07/202,505, filed Jun. 6, 1988, by Paul G. Cheng and one of the present applicants (Kurt Baum), which is a division of U.S. patent application Ser. No. 07/020,361, filed Mar. 2, 1987. Both of those applications contain subject matter presently under a Secrecy Order, although the parent application is now abandoned and the divisional application is slated to be abandoned for failure of applicants to respond to an Office action thereon. More specifically, the method of synthesizing diamines disclosed in these two patent applications takes the following route. ##STR1##
Copending U.S. patent application Ser. No. 07/350,130, filed May 8, 1989, by Baum, Malik, and Tzeng (Baum and Malik being two of the present applicants), discloses a method of converting the aforesaid diamines to diisocyanates by first bubbling gaseous hydrogen chloride into suspensions of the diamines in a suitable solvent, then introducing phosgene at temperatures up to 130.degree. C. to form the diisocyanates. That copending application also discloses that analogous monofunctional isocyanates can be prepared by the same reaction scheme. Such monofunctional isocyanates are potentially useful for fabric soil-resistance treatment by reacting with hydroxyl groups in the fabric.
Diols having the formula HO--CH.sub.2 CH.sub.2 --(CF.sub.2).sub.n --CH.sub.2 CH.sub.2 --OH, in which n is 4 or 6, have been reported, and similar diols where n is from 1 to 20 have been claimed in a Japanese patent (Asahi Glass Co., Jpn. Kokai Tokkyo Koho JP 82 99,552, Jun. 21, 1982).
The reaction of perfluoropropylene with 1,4-diiodoperfluorobutane has been reported to give a mixture of telomers (G. Caporiccio, G. Bargigia, C. Tonelli and V. Tortelli, Eur. Pat. Appl. EP 200,908, December 1986; Chem Abstr., 107 6762. ##STR2##